Internal-combustion engine.



H. C. L. HUMAN.

INTERNAL COMBUSTIQN ENGINE. APPLICATION FILED FEB. 11. I915.

Patented Apr. 23, 1918 3 $HEETS-SHEET I- H. C. L. TIDMAN.

INTERNAL COMBUSTION ENGINE. APPLICATION FILED FEB. 17f1915.

Patented Apr. 23, 1918.

3 SHEETSSHEET 2.

H. C. L. HUMAN.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED FEB. H. 1915.

Patented Apr. 23, 1918.

3 SHEETSSHEET 3.

r J 5 F i E i i i g L--. g L l //M f/VT9/E s ratus rA'tEN @FFtCE- HERBERT CHARLES LIVINGSTONJE TIDMAIF, 0F WESTON-SUPEJR-MARE, ENGLAND.

INTERNAL-COMBUSTION ENGINE.

To all whom it may concern:

Be it known that l, HERBERT CHARLES Lrvmcsronn TIDMAN, a subject of the King of Great Britain and Ireland, and resident of Weston-super-Mare, county of Somerset, England, have invented a certain new and useful Improvement in Internal-Combustion Engines, of which the following is a specification,

This invention relates to internal combustion engines, and more particularly has special reference to an improvement in the means for controlling the admission of the gaseous fuel and the exhaust of the spent or dead gases in'two-cycle internal combustion engines.

@ne of the objects ofthe invention is to provide for an effective displacement of the exploded charge and the replacing of a fresh charge with the least possible loss of compression of the latter, and at the same time utilizing a part of the new charge to assist in the scavenge of the cylinder.

A further object of the invention is to provide a novel type of port or sets of ports for accomplishing the above ends, without the use of separate valve devices.

With the above and other objects in view which will more readily appear as the nature of the invention is better understood, the same consists in the novel construction, combination and arrangement of parts hereinafter more fully described, illustrated and claimed.

My invention is illustrated in the accompanying drawings, in which Figure 1 shows one type of port c0ntemplated by the present invention.

Fig. 2 shows a modification of the ports shown in Fig. 1.

Fig. 3 is a side elevation of a two-cycle combustion engine embodying the present invention.

Fig. 4 is a' view of the opposite side of the engine shown in Fig. 3.

Fig. 5 is an enlarged vertical sectional view of one of the engine cylinders shown in Fig. 3.

Fig. 6 is a view similar to Fig. 5 taken at right angles thereto.

Similar reference characters designate corresponding parts throughout the several figures of the drawings.

As previously indicated, one of the ob ects of this invention is to provide means for Specification of Letters Patent.

charge as quickly as possible, while at the same time retaining the greatest amount of compression, thereby not only conservingthe eiiiciency of the fresh charge but also materially assisting in the expulsion ofq the dead gases.

To this end, it is proposed to employ a novel type of inlet and exhaust ports, shown in Figs. 1 and 2, and by way of illustrating their use and embodiment in an internal combustion engine, reference may be had to Figs. 3 and 6 inclusive. Figs. 3 and 4:, respectively, show opposite sides of a twocycle engine wherein the pistons are of the tandem type, and the cranks set at an angle of 180. In these figures, the upper cylinders 12 are the water jacketed working cylinders, while the lower cylinders 3-4 are the compressors which are joined with the working cylinders by suitable cross-overs. Thus, as will be seen from Fig. 3, the compressor 3- compresses for working cylinder 2, and compressor 4 for working cylinder 1. In Fig. 4:, the opposite side of the engine is shown, the carbureter 0 being connected with the compressor cylinders 4-3 and the exhaust pipe E being common to both working cylinders 21'.

As the working cylinders are of similar construction, a description of one will suffice for the other. Therefore, referring to Figs. 5 and 6, showing the interior construction of the cylinder, it will be observed that the reference character 5 designates inlet chamber of the cylinder which receives the compressed fuel charge from the cross-over connected with the compressor 4, and which communicates with the interior of the Working cylinder by means of the ports a such as shown in Fig. 1 of the drawings. The reference 6 designates the exhaust chamber of the cylinder 1 which is diametrically opposite the inlet chamber 5 and communicates with the interior of the cylinder by means of the ports a which are similar in shape and form to the ports shown in Fig. 1. This exhaust chamber opens into the exhaust manifold E.

Within the working cylinder 1 operates the piston 7 the upper portion of whlch operates within the working cylinder 1', and includes the piston head 8, having the skirt Patented Apr. 2%, ram. Application filed February 17, 1915. Serial No. 8,877.

till

shown in Fig. 5 of the drawings, it will be understood that the fresh fuel charge enters the ports a under compression and is de flected upwardly into the cylinder 1 by the deflecting plate 10, thus assisting in driving out the spent gases not already exhausted through the exhaust port a. At the same time, the above action takes place, gaseous fuel is drawn through the port 12 from the carbureter into the compression chamber 3 so that upon the upstroke of the piston, the fresh fuel charge will be compressed and expelled through the port 13 to the working cylinder 2. It will, of course, be understood, that the up stroke of the piston which supplies fuel to the cylinder 2, closes the ports a and a and compresses the l1ve fuel charge in the cylinder 1 in the usual manner until it is ignited by a conventional sparking device not shown.

Referring further to Figs. 1 and 2 of the drawings, showing the type of ports employed in the present invention, it will be noted that ports of the same shape are used as both inlet and exhaust ports, it, of course, being understood that different sets of ports are used for the different functions. In Fig. 1, the port consists of a plurality of port units designated by the common reference a. That is to say, the entire port may consist of any number of port units including the openings 00 and g which as shown in this figure are separated by an intervening wall 2. Thus, as the piston 7 falls in a cylinder having ports of this character, its upper edge will, in its downward travel, first uncover the relatively large upper part of the openings 0:, thus permitting a relatively large flow or passage of gases initially, which rate of passage is maintained while the piston moves down to where the sides of the opening 00 begin to narrow and then the passage of gas is temporarily held fixed by the wall 2, and a greater passage is not again resumed until the piston uncovers the opening 3 of the port unit. In other Words, a relatively large volume of gas is permitted to pass through the upper openings of the port units comprising the entire port as soon as piston in its down stroke enters the zone of the openings w, and then the volume of gas passing through the entire port is held substantially constant for a fractional eriod of time, and then the port is opened Full length to complete the passage of the gases.

From the foregoing, it will be apparent that the ports regulate both the intake and exhaust of gases. That is to say, the shape and character of the ports cooperating with the upper edge of the piston, which is a relatively constant factor, regulates both the volume and speed of the gases passing into and out of the cylinder to the best advantage for effecting apomplete scavenge and conserving compression.

The same general character of ports as above described are shown in Fig. 2 of the drawings, wherein it will be observed that instead of providing a solid wall between the upper and lower openings :11 and y, the same are connected by a restricted passage 6, the inwardly projecting wall portions 2 operating to give substantially the same retarding efi'ect to the passage of the gases as the wall 2 in Fig. 1. This type of port is advantageous under some conditions, and while the openings 02 and y of each port umt are in communication by the restricted passage 6, the same result is attained as in F 1g. 1, except, however, the retarding of the gases is not as pronounced when the upper edge of the piston passes over the middle or intermediate portion of the ports. This type of port may be advantageously useddwhere the engine is designed for high spee As will be observed from Figs. 5 and 6 of the drawings, the inlet and exhaust ports designated generally as a and (1, respectively, each include a plurality of port units comprising the openings :12 and 3 of different area which are spaced from each other whereby when they are uncovered by the edge of the piston, the gases passing therethrough are retarded at an intermediate point in the travel of the piston across the unit. Thus, when the piston shown in Fig. 5 for instance, is up in the working cylinder 1, and the compressed charge above the head thereof is fired, the piston recedes from the cylinder head until it travels far enough to uncover the openings at of the port-units of the exhaust port designated generally as a; and at the same time corresponding openings w of the units of the inlet port designated generally as a are also uncovered. When the upper openings at of both are uncovered, the dead gases exhaust through the openings in the port a and the compressed new charge rushes out of the openings at of the inlet port a against the deflecting plate 10 and thence up the side of the cylinder opposite the exhaust port.

Then, as the piston travels over the middle third of the group of port units, it passes over the wall 2 between the openings 00 and llll 1,aee,eao all 3 of each unit, and the area of both inlet and exhaust ports is temporarily held fixed, or in other words, not increased proportionately as would be the case if the sides of the port were uniformly parallel.

As the piston passes over this middle third or wall a of the ports, the exhaust of the dead gases is prevented from taking place more rapidly than the openings m of the port a will permit, and likewise, the pressure of the new gas coming in theopenings m of the inlet port a will be held temporarily fixed, thus giving the new gas within the cylinder, an opportunity to expand somewhat before further live fuel is admitted and thereby utilizing the expansion of what live fuel was initially admitted to drive out some of the dead gases! In other words, this temporary restriction of the passage of gases through both inlet and exhaust ports permits the utilization of the expansion of a part of the new charge to drive out the dead gases, so that when the balance of the live fuel 1s admitted, its compression is greatly conserved and waste thereof prevented. 0bviously, if the full new charge were admitted all at one time, some of it might go out with the dead gases, and much of its compression would be lost. However, in the present invention such can not be the case, because similar sets of inlet and exhaust ports are so shaped that the piston first permits an initial exhaust of the dead gases and a par tial admission of live gas under pressure, whereby the latter expands and pushes the dead gases farther toward the point of perfeet scavenge, so that when both sets of ports are opened full, live gas, is fully admitted and the dead gas is fully expelled except for what is further expelled by the expansion of the new charge at the beginning of the return stroke of the piston.

Upon the return stroke, the piston first closes the-similar port openings 3 of both lib intake and exhaust ports and then after passing the relatively closed or restricted areas 2 passes over the large openings 00 thereby of the cylinder.

assisting in the complete scavenge Accordingly, it will be apparent that the present invention has in view a novel construction and arrangement of ports which may be used as intake and exhaust ports, and which coact with the piston to vary the speed of the passage of gases to and from the cylinder, whereby the initial part of the incoming charge is utilized as a scavenging agent, so that when the full live charge is admitted, thegreater part of the dead gas will be expelled by the expansion of the first part of the compressed live'charge admitted to the cylinder, and the compression of the balance of the live charge admitted will be materially conserved.

I claim:

1. In an internal combustion engine the combination with the piston and the cylinder, of inlet and exhaust ports formed in the walls of the cylinder and consisting of a plurality of port units each including an upper openin having a; substantially fiat upper edge, su stantially parallel side edges, and a circular bottom edge, and a lower opening of circular shape.

2. In an internal combustion engine, the combination with thepiston and the cylinder, of inlet and exhaust ports formed in the walls of the cylinder and consisting of a plurality of port units each including an fipper opening having a relatively flat upper edge, substantially parallel side edges and a circular bottom edge, a lower opening of circular'shape, and a passageway connecting said upper and lower openings.

3. In an internal combustion engine the combination with a piston and a cylinder,

of inlet and exhaust ports formed in the cylinder consisting of an openin having a relatively flat edge, substantial y parallel opposite edges and a circular edge opposite the said relatively flat edge, and another opening 0 circular shape.

lln testimony whereof I have afixed my signature in presence of two witnesses.

HERBERT CHARLES LIVINGSTQNE TIDlllAN. Witnesses:

E. J. FUSSELL, H. Woons. 

